Northwest NEWS

March 11, 2002

Traffic lights better than roundabout

I commute through the intersection of SR 203 and Northeast 124th Street every day and after asking some questions and doing some thinking, I have to say I don't understand what would make a roundabout the best solution to the shortcomings of this particular intersection.
Unlike some other readers who have written letters about this, I feel that a solution to a problem should be neither favored nor disfavored because it is innovative. The real question should be, is it a GOOD solution to the problem we want to solve?
According to WSDOT staff, in the last three years of accident records there were 11 accidents at this intersection, of which several involved a car starting a left turn being sideswiped by another car trying to pass that car. The only accident out of the 11 that involved serious injuries was also the only one of its kind: a car turning left from 124th onto SR 203 being hit by another car going south on SR 203.
A roundabout is definitely overkill when it comes to the sideswipe accidents. The obvious and inexpensive solution to those accidents is to change the broken yellow line down the middle of SR 203 to a solid double line, so that it is no longer legal to pass at this intersection.
A well-marked roundabout likely would have prevented that lone serious-injury accident. So would a traffic light.
As everyone who has ever waited in line on 124th Street in the afternoon knows, this intersection suffers from problems. Here is where I think traffic signals would outshine a roundabout because of their far superior flexibility.
A roundabout, once it's built, is what it is. But traffic signals can be programmed to do different things at different times of the day and days of the week and is fairly easy to upgrade when the need arises.
During the weekday afternoon rush, the traffic signals could be set to give 124th Street traffic plenty of green-light time.
The rest of the time, the 124th Street signals could be set to flashing red (equivalent to the way things are all the time, now). Or for improved safety, but some sacrifice of efficiency, the 124th Street signal could be set to turn green only after a car pulls up to the stop bar.
Left-turn lanes would be needed on SR 203, but wouldn't need to be very long because not that many cars turn left onto 124th during the afternoon rush. For the same reason, the left-turn traffic would not need its own green light. Because so little traffic comes from the east on 124th, no left turn lanes would be needed on 124th.
My guess is that the above-described work would be cheaper than a roundabout Ñ especially a roundabout big enough to safely handle Cadman's double dump trucks.
But even if it costs the same, it could handle non-rush-hour traffic (those other 21 hours in the day) quite a bit better and would also give northbound trucks a better chance to get through the intersection during rush hour. It would thus be the better choice for serving the public.
Roundabouts are attractive to highway agencies because of reduced maintenance headaches Ñ no midnight trips to fix the signals after a storm knocks them out.
I have no idea how strongly this factored into WSDOT's decision to propose a roundabout, but it is reason for citizens to be cautious about assuming the highway department "must know best."
Karen J. Williams, Duvall